initial sound

	modified:   cg-st-adv.userprefs
	modified:   st-adv-Main/Content/UserMenu/UserMenu.cs
	new file:   st-adv-Main/Utilities/Sound/Sound.cs
	new file:   st-adv-Main/Utilities/Sound/SoundInit.cs
	modified:   st-adv-Main/st-adv-Main.csproj
Merge branch 'Sound' of https://github.com/fin-ger/cg-st-adv into Sound

Conflicts:
	cg-st-adv.userprefs
	st-adv-Main/Utilities/Sound/Sound.cs